Tips & Techniques
For Container Gardening
Using Annuals, Perennials & Grasses
by Linda Anson

THE BASICS

CONTAINERS

• Larger are better than smaller, at least 12" wide and 12" deep (any smaller and they're prone to freezing and need to be watered constantly)
• Be sure they're clean and free of disease
• Must have good drainage, 3-7 1/2" holes, depending on the container. Cover holes with shards to minimize loss of mix through the holes.

GROWING MEDIUM

• Must drain well.
• Be lightweight - helps for good root growth
• Must be sterilized to avoid insects, diseases and weed seeds.

Soilless potting mixes are now quite good and the easiest way to go. Look for the following ingredients:
        Peat moss   --      organic material
Vermiculite or perlite aerates (vermiculite both aerates and absorbs water and nutrients)
        Limestone   --     balances pH

Many of the newer mixes also contain wetting agents, nutrients and polymers. To test a potting mix: Squeeze it in your hand. - The mix should hold together when compressed, but crumble easily when tapped.

Note: For containers, use a potting mix that's somewhat coarse. The finer mixes, like those that can be used to start seeds, will become dense and cause the roots to suffocate.

Note: Peat moss is slow to absorb moisture, so moisten the mix before using it, but don't let it be soggy.

PLANTING METHOD

* Mix slow-release fertilizer into moistened potting mix using manufacturer's directions. (If purchased potting mix contains some nutrients, you probably still want to add some slow-release, such as 14-14-14, but read the potting mix bag carefully to determine content. Note: An 8-9 month slow-release formula will last longer in heat than the 3-4 month slow-release formulas.)

* Fill container about 3/4 full of the mix.

* Pre-arrange your chosen plants to be sure you like the grouping and placement.

* Starting the center, remove the plant from its pot, gently loosen and spread roots. Plant closely (more closely than you'd plant in the ground).

* Add more moistened potting mix to within one inch of the top.

* Water thoroughly.

 

 

MAINTENANCE

Fertilizing

Frequent watering washes out nutrients, so you need to provide a constant supply of nutrients. For annuals especially, supplement the slow-release fertilizer with water-soluble 20-20-20 every two weeks. Alternatively, you can add a weak solution of fertilizer each time you water.

Grooming

Remove spent blossoms and brown leaves. Removing spent blooms encourages strong growth and continued heavy flowering. Check for insects and diseases before they spread.

Watering

• Check for need to water every other day, and every day in hot weather.
• Don't just use your eyes - stick your finger into the soil! If soil is dry down to 1", then you need to water.
• The best time to water is early in the morning. If you must water in hot, sunny weather, avoid splashing the leaves, which can scorch.
• Water thoroughly, but never allow water to stand in saucers or drip trays. Consider using feet for your containers - they help with drainage and protect your deck or patio.
• Be aware that some planting mediums are almost impossible to remoisten if allowed to dry out.
• Consider adding the gels/polymers that hold water for later release, but don't depend on them entirely. Remember that if the container has dried out too much before watering, the polymer can actually pull water out of the roots of the plants! And follow the manufacturers directions exactly. A very little goes a long way!

DESIGN CONSIDERATIONS FOR CONTAINER GARDENING

CONTAINERS

What's a container? Even an old rowboat can be a container! Use your imagination.

PLACEMENT

Within a garden bed?
On a set of steps?
For screening?
To enclose a patio?
To frame an entrance or bench?

GROUPING

Seldom use just a single container

Groupings should have a unifying element, such as identical containers, or containers made of the same material, but of varying shapes/sizes.

STYLE OF CONTAINER

Formal or informal? A very formal container can enhance a more formal setting, whereas informal containers seldom do. Consider the "look" you're trying to achieve when selecting a container.

STYLE OF PLANTING

Formal or informal? Again, consider the "look" you're conveying. Informal plantings can be done in formal containers, but the reverse is usually difficult to achieve successfully.

PLANT COMBINATION GUIDELINES

First, there's nothing wrong with using just a single plant! Can be very elegant in a beautiful container.

When combining plant materials, consider

• Sun vs. shade
• Dry vs. moist requirements
• Growth rates
• Textures, forms and mature heights - Strive for contrast!

When combining plant materials, consider a mix of uprights, trailers and fillers.